This post is amazing and at the same time frustrating.
You need to tell us more about this if some actual digging is going to be successful. He told you that many of his samples came from that specific stack of cds you were looking through? Does it mean that they were all released on cd? Searching some of these artist catalogs looking for samples is just impossible since some of the artists are quite famous and samples havent been found yet in cases like:
Black Ivory
Blue Magic
Brook Benton
The Markeys
Mandrill
The Meters
Burt Bacharack
Mary Wells
Billy Preston
The Delphonics
Harold Melvin & The Blue Notes
Three Degrees
Bobby Womack
The JB's
The Stylistics

Tell us more.

^
Bro diggin is all about sitting down and listening to music untill you find that gem.
You can go through a record many times and hear nothing,
then boom!!!
there its is!!...
And with that list you made up there,
theres endless samples in that list.
Do the knowledge first.
And who cares if 4th didn't or did use some of those artists,
the point is he has them in his collection,
so there's a high possibility that he sampled them.
Wanting to know exact details is funnystyle!